532 research outputs found

    Microscale investigation of complex liquids porous media

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    The interaction of Non-Newtonian fluid and porous media is a topic of great scientific interest and it finds application in a wide number of industrial fields: from the enhanced oil recovery to the drug delivery. In particular, a very interesting category of liquids are the so-called property called "yield stress fluids". These systems have the ability to behave as solids under this stress threshold and to flow as liquid above it. Numerous studies have been performed in this sense even if the mechanism on a microscale level still have not been completely elucidated. In this work, we identified some model systems such as polyacrylic acid (Carbopol)-water solutions and by the use of confocal microscopy we looked at the microstructure of the gel to understand the origin of the yield stress and how the confinement and the flow have an impact on this microstructure. It has been observed that the swollen particles of Carbopol build a 3D network whose connectivity causes the yield stress. Furthermore, the system can be described as two phases at equilibrium since the particle concentration does not influence the properties of the solvent phase. Changing the temperature, a phase diagram has been drafted finding analogies with typical polymeric systems, finding a miscibility gap. These learnings helped developing a novel experimental tool based on a torsion pendulum equipped with a magnetic dipole and a rotating cylinder immersed in the material, to measure yield stress in gels able to discriminate dynamic and static yield stress. At the end, an alternative system as detergent foams, has been studied focusing on the process of formation in sponges, in order to understand the effect of surfactant and sponge material on the foamability of the system. Our experimental data revealed that using a lower confinement in the foam formation allows the production of a drier foams (i.e. with lower liquid fraction, φL<0.3), more similar to the ones obtained in dish-washing applications. Our results are of potential interest for the optimization of foams in complex structures, such as in deformable porous media

    An evaluation of the economic impact of Climate Change through a three-stages Discrete Stochastic Programming model

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    The climate change in the agricultural sector acting on multiple weather variables at different times of the various crop cycles. In several cases by changing the mean level of variables (rainfall, temperature, etc..), in other cases by changing the distribution of events. This work provides an evaluation of the economic impact due to changes in multiple events, and to the associated uncertainty. For this reason, a classical two-stage stochastic programming model was extend into a three-stages model. The model is specified for an area of Sardinia, and examines the impact of climate change on rainfall and hence on the availability of water for agriculture, and on maximum temperatures and, therefore, on the requirements of some irrigated crops relevant to the agricultural economy of the area. The effect of climate change is obtained by comparing the results of scenarios that represent the climatic conditions in the current situation and in the future, obtained by projecting to 2015 the climate trends of the last fifty years. The results show that the agricultural sector of the area adapt itself with a low cost by use of land and cultural practices. This cost, however, is very high for some farms that suffer a significant reduction of the income. There is also an increase of the use of natural resources, in particularly groundwater. The economic impact of these changes is due primarily to the decreased of water availability in the future. The availability of water becomes the crucial factor to adapting to climate change, because the effects of temperature can be compensate by increased the use of water resources.Discrete Stochastic Programming Model, climate change, water availability, irrigation requirements, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use, Research Methods/ Statistical Methods,

    Evoluzione del clima e incertezza delle scelte sui sistemi colturali in un comprensorio irriguo del Nord Sardegna

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    L’analisi quantitativa dell’impatto dei cambiamenti climatici (CC) sui sistemi colturali implica l’impiego di modelli di simulazione adeguatamente calibrati. Il modello EPIC (Environmental Policy Integrated Climate) (Williams, 1995) è stato ampiamente validato per simulare le risposte delle colture e dei relativi fabbisogni idrici ai CC (Adejuwon, 2005, Tourè et al., 1994). In questo lavoro, i risultati delle simulazioni effettuate con EPIC sono stati utilizzati come input per il modello di analisi economica per valutare l’impatto del CC sulle scelte dei sistemi coltutali in un comprensorio irriguo della Sardegna del nord

    Lesioni non palpabili della mammella: la Mammotome-biopsy nella gestione preoperatoria del cancro della mammella

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    Premessa: Il tumore del seno è nei paesi occidentali al primo posto per frequenza nelle donne e la sua incidenza è in costante crescita. Grazie soprattutto alla diffusione dello screening mammografico e ad una maggiore consapevolezza del problema, negli ultimi anni è aumentata la diagnosi delle cosiddette lesioni “non palpabili”; parimenti si è assistito ad un importante sviluppo delle metodiche diagnostiche di tipo mininvasivo. Alla tradizionale citologia con ago sottile si sono affiancate infatti varie procedure bioptiche percutanee; tali metodiche microistologiche hanno quasi del tutto sostituito la biopsia chirurgica escissionale e l’esame intra-operatorio al congelatore. Pazienti e metodo: Nella nostra Divisione di Chirurgia Generale, Vascolare e Mininvasiva, dal dicembre 1999 al settembre 2004 abbiamo eseguito, in collaborazione con il servizio di Radiologia, 214 biopsie su guida ecografia utilizzando la vacuum-assisted biopsy (Mammotome® ) con ago 11-Gauge. I risultati ottenuti per ciò che concerne l’accuratezza diagnostica, la quantità e qualità delle informazioni ottenute, il significato delle stesse nella eventuale gestione chirurgica, il discomfort globale per la paziente sono stati analizzati e discussi nel presente lavoro. Risultati: Delle 214 biopsie eseguite con tecnica Mammotome, nell’89,3% dei casi si è trattato di lesioni clinicamente non palpabili, con un diametro medio di 8 mm. L’età media delle pazienti era di 57,6 anni (range 31-88). La positività per patologia maligna è stata di 90 casi (42%). Nei casi di iperplasia duttale atipica e radial scar (6%) è stata effettuata l’exeresi chirurgica della lesione che ha confermato nel 100% dei casi la precedente diagnosi bioptica. Il 19% delle pazienti sottoposte a biopsia Mammotome era stato precedentemente sottoposto ad un prelievo citologico con ago sottile. Confrontando i risultati delle due metodiche, l’attendibilità diagnostica della seconda risulta essere significativamente superiore (p<0,05) come pure il numero di informazioni ottenute (istotipo, invasività, grading, recettori ormonali, etc.); il discomfort legato alla procedura, valutato in termini di dolore (VAS), è risultato inferiore a quello del prelievo con ago sottile (p<0,05). L’unica complicanza della biopsia Mammotome è rappresentata dall’ematoma nella sede del prelievo (8% dei casi). Il numero dei falsi negativi è stato di un caso, dovuto ad un non corretto centraggio del bersaglio. Conclusioni: Allo stato attuale in presenza di una lesione non palpabile della mammella la scelta della metodica diagnostica (agobiopsia o Mammotome) è legata al sospetto radiologico nella prospettiva di un eventuale intervento chirurgico. La biopsia con Mammotome nelle lesioni non palpabil

    Linear Accelerator Test Facility at LNF Conceptual Design Report

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    Test beam and irradiation facilities are the key enabling infrastructures for research in high energy physics (HEP) and astro-particles. In the last 11 years the Beam-Test Facility (BTF) of the DA{\Phi}NE accelerator complex in the Frascati laboratory has gained an important role in the European infrastructures devoted to the development and testing of particle detectors. At the same time the BTF operation has been largely shadowed, in terms of resources, by the running of the DA{\Phi}NE electron-positron collider. The present proposal is aimed at improving the present performance of the facility from two different points of view: extending the range of application for the LINAC beam extracted to the BTF lines, in particular in the (in some sense opposite) directions of hosting fundamental physics and providing electron irradiation also for industrial users; extending the life of the LINAC beyond or independently from its use as injector of the DA{\Phi}NE collider, as it is also a key element of the electron/positron beam facility. The main lines of these two developments can be identified as: consolidation of the LINAC infrastructure, in order to guarantee a stable operation in the longer term; upgrade of the LINAC energy, in order to increase the facility capability (especially for the almost unique extracted positron beam); doubling of the BTF beam-lines, in order to cope with the signicant increase of users due to the much wider range of applications.Comment: 71 page

    Two novel PRNP truncating mutations broaden the spectrum of prion amyloidosis

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    Truncating mutations in PRNP have been associated with heterogeneous phenotypes ranging from chronic diarrhea and neuropathy to dementia, either rapidly or slowly progressive. We identified novel PRNP stop-codon mutations (p.Y163X, p.Y169X) in two Italian kindreds. Disease typically presented in the third or fourth decade with progressive autonomic failure and diarrhea. Moreover, one proband (p.Y163X) developed late cognitive decline, whereas some of his relatives presented with isolated cognitive and psychiatric symptoms. Our results strengthen the link between PRNP truncating mutations and systemic abnormal PrP deposition and support a wider application of PRNP screening to include unsolved cases of familial autonomic neuropathy

    Sex differences in the efficacy and safety of SARS-CoV-2 vaccination in residents of long-term care facilities: insights from the GeroCovid Vax study

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    Despite the reported sex-related variations in the immune response to vaccination, whether the effects of SARS-CoV-2 vaccination differ by sex is still under debate, especially considering old vulnerable individuals, such as long-term care facilities (LTCFs) residents. This study aimed to evaluate COVID-19 infections, adverse events, and humoral response after vaccination in a sample of LTCF residents. A total of 3259 LTCF residents (71% females; mean age: 83.4 +/- 9.2 years) were enrolled in the Italian-based multicenter GeroCovid Vax study. We recorded the adverse effects occurring during the 7 days after vaccine doses and COVID-19 cases over 12 months post-vaccination. In a subsample of 524 residents (69% females), pre- and post-vaccination SARS-CoV-2 trimeric S immunoglobulin G (Anti-S-IgG) were measured through chemiluminescent assays at different time points. Only 12.1% of vaccinated residents got COVID-19 during the follow-up, without any sex differences. Female residents were more likely to have local adverse effects after the first dose (13.3% vs. 10.2%, p = 0.018). No other sex differences in systemic adverse effects and for the following doses were recorded, as well as in anti-S-IgG titer over time. Among the factors modifying the 12-month anti-S-IgG titers, mobility limitations and depressive disorder were more likely to be associated with higher and lower levels in the antibody response, respectively; a significantly lower antibody titer was observed in males with cardiovascular diseases and in females with diabetes or cognitive disorders. The study suggests that, among LTCF residents, SARS-CoV-2 vaccination was effective regardless of sex, yet sex-specific comorbidities influenced the antibody response. Local adverse reactions were more common in females

    Humoral immunity induced by mRNA COVID-19 vaccines in Nursing Home Residents previously infected with SARS-CoV-2

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    Background: Nursing home (NH) residents suffered the greatest impact of the COVID-19 pandemic. Limited data are available on vaccine-induced immunity and on the protection ensured by a prior infection in this population. Aims: The present study aims to monitor antibody levels and their persistence over a 6-month period in NH residents according to the history of prior SARS-CoV-2 infection. Methods: We measured anti-trimeric Spike IgG antibody levels in a sample of 395 residents from 25 NHs in 6 Italian Regions at study enrolment (prior to the first dose of vaccine, T0) and then after 2 (T1) and 6&nbsp;months (T2) following the first vaccine dose. All participants received mRNA vaccines (BNT162b2 or mRNA-1273). Analyses were performed using log-transformed values of antibody concentrations and geometric means (GM) were calculated. Results: Superior humoral immunity was induced in NH residents with previous SARS-CoV-2 infection. (T0: GM 186.6 vs. 6.1 BAU/ml, p &lt; 0.001; T1: GM 5264.1 vs. 944.4 BAU/ml, p &lt; 0.001; T2: GM 1473.6 vs. 128.7 BAU/ml, p &lt; 0.001). Residents with prior SARS-CoV-2 infection receiving two vaccine doses presented significantly higher antibody concentration at T1 and T2. A longer interval between previous infection and vaccination was associated with a better antibody response over time. Discussion: In a frail sample of NH residents, prior SARS-CoV-2 infection was associated with a higher humoral response to vaccination. Number of vaccine doses and the interval between infection and vaccination are relevant parameters in determining humoral immunity. Conclusions: These findings provide important information to plan future immunization policies and disease prevention strategies in a highly vulnerable population
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